WORCESTER — The Worcester Public Library board of directors scrambled Tuesday evening to name an interim head librarian after Christopher Korenowsky stepped down barely five months after taking over as library chief.

Mr. Korenowsky's abrupt resignation hit at a time when the library has no associate head librarian to step in and run the institution on short notice.

Mr. Korenowsky is the city's third head librarian to resign in roughly two years, according to library board members.

The library board discussed his resignation behind closed doors for about an hour Tuesday evening but declined to give any public explanation for the sudden departure. Mr. Korenowsky was not at the meeting and couldn't immediately be reached for comment Tuesday evening.

“All we can say is Chris is no longer employed by the library,” said Deborah Packard, president of the library board.

After a sometimes contentious debate, the divided board voted 5-4 to hire a recent board member to temporarily run the library as interim head librarian for approximately three months while yet another search for a permanent head librarian is mounted.

The board's choice of Tracey Leger-Hornby as interim head librarian required City Council approval because the state conflict of interest law otherwise bars a municipal board from hiring a former member less than a month after he or she stepped down.

The City Council granted the waiver unanimously during its regular meeting Tuesday night, but not without some grumbling about the turnover in the library's upper ranks. District 2 City Councilor Philip Palmieri requested a report from City Manager Edward M. Augustus Jr. about the management problems at the library.

Mr. Augustus described the latest resignation as a “unique personnel issue” without elaborating on the situation.

A city lawyer and a human resources specialist attended the library board meeting to advise the panel on the process for appointing an interim head librarian.

Ms. Leger-Hornby, a consultant who previously was the dean of library services at Worcester Polytechnic Institute, was named to the city library board about six months ago but then had to submit her resignation because she moved out of Worcester.

Only residents are permitted to serve on the board.

Her resignation from the board was accepted at Tuesday's meeting, shortly before she was then named the new interim head librarian.

Board members William S. Coleman III, Joshua Perro, William Belcher and Collins Nuamah voted against hiring Ms. Leger-Hornby to temporarily run the library, saying the board should at least try to seek other candidates in a public process.

“The perception the library board is putting out there by not considering any other candidates is important,” said Mr. Coleman, who tried unsuccessfully to get the board to seek other candidates for at least a week.

But James Kersten, the board's vice president, argued in favor of decisive action to fill the leadership vacuum.

“There's turmoil going on right now,” Mr. Kersten said. “We really need to steady the waters, and we do that by moving quickly.”

He was joined by Ms. Packard and board members Judy Finkel, Dianne Bruce and Jacob Sanders in passing the motion to hire the former board member.

Ms. Leger-Hornby will run the library on a day-to-day basis while the board looks for a permanent replacement for Mr. Korenowsky. Her consulting business has one client in Boston that she will continue working for part time while running the Worcester library, Ms. Packard said.

When Mr. Korenowsky was hired late last winter, the quality of candidates applying for the job was not as high as the board would have liked, Mr. Kersten said.

While the library has continued to move forward on a number of initiatives in recent years, any perception of turmoil in the library's management could hinder efforts to attract a highly qualified candidate.

Mr. Korenowsky, who was named to the position in February and started in March, was the fourth head librarian since Penelope Johnson retired in 2009 after 18 years at the helm, not counting an associate director who served on an interim basis. Ms. Johnson's successor, Lucy Gangone, left in March 2010. The next head librarian, Mark Contois, left in 2012 and was succeeded by Wei Jeng-Chu, who retired last year. John Weedon was interim head librarian before Mr. Korenowsky was hired.

Ms. Jeng-Chu is out of the country for several months and was not available to step in as interim head librarian for a few months, Ms. Packard said.

“If we don't act tonight, I think it will be a month or more before we have somebody in place,” Ms. Packard said before the vote.

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